A. Field of the Invention
The present invention relates to a cosmetic composition for the treatment of hair, in particular oily hair, containing a dry extract of yarrow (Achillea millefolium L) obtained by oxidation of a water-alcohol extract of the flower tops of yarrow.
B. Description of the Prior Art
Different extracts of yarrow have been proposed for the treatment of hair. For example, French Patent No. 78,22837 describes the utilization of an extract of yarrow rich in polyphenolic derivatives of the flavonoid group in the manufacture of bleaching shampoos.
Preparation of the extract according to the invention must be carried out under conditions which do not lead to any degradation of polyphenolic derivatives, which are particularly sensitive to heat.
The essential oil of yarrow is a volatile oil which has been promoted by different authors in the field of cosmetics for the treatment of oily skin and for the treatment of hair seborrhea, the essential oil of yarrow possessing antiseptic and anti-inflammatory properties due to the relatively high percentage of azulene therein.
The essential oil of yarrow consists essentially of azulene, .alpha.- and .beta.-pinene, caryophyllene, borneol, terpineol, cineole, bornyl acetate and other volatile components of diverse structures.
The utilization of extracts of yarrow, in particular water-alcohol extracts, up to now has given rise to certain difficulties. The extracts of yarrow have been found to possess a sensitizing action on certain subjects, thereby provoking allergic phenomena (see "Encyclopedia of common natural ingredients used in Food, Drugs and Cosmetics" by Albert Y. Leung, Wiley, 1980, p. 326).
After several studies on water-alcohol extracts of yarrow were completed, it was ascertained, surprisingly, that the allergenic properties could be reduced and even suppressed by submitting the water-alcohol extract solutions to an oxidizing treatment. Dry extracts of yarrow obtained after this treatment are devoid of sensitizing power but nevertheless retain the particular properties effective for the treatment of the oily appearance of hair, while also conferring softness and luster to the hair.
However, it was suspected that subjecting the water-alcohol extracts of yarrow to an oxidizing treatment, in order to eliminate the sensitizing power, would simultaneously provoke a deterioration of the active ingredients for the treatment of oily hair. However, tests have been carried out which prove that this activity is preserved and even enhanced.
The dry extracts of yarrow after oxidation are characterized by a very low content of polyphenolic derivatives and by the absence of polysaccharidic polymers and essential oil.